AirPlay for all? Miracast promises video streaming without the router

WiFi Alliance takes a stab at vendor-neutral interoperability.

This cartoon family has discovered the joys of vendor-neutral video streaming.

WiFi Alliance

Streaming audio and video from a handheld device to a TV is relatively easy these days, provided you don't mind getting locked in to one vendor.

From Apple, you have AirPlay for streaming from iPhones and iPads to televisions (through the Apple TV). Somewhat similarly, Google's forthcoming Nexus Q media player streams from the cloud and is controllable by an Android device, letting you start a show on your Android phone or tablet and finish it on a TV (or vice versa). Microsoft and Nokia, meanwhile, are preparing a "Play To" app that will let Windows phones stream to any TV, provided it is DLNA-certified.

Ideally, you could buy any smartphone or tablet from any vendor and use it to stream content to any TV. We're pretty far from that point, but a new program called Miracast from the WiFi Alliance industry group is likely the most promising attempt at such vendor-neutral interoperability to date. Coming within the next few months, Miracast is a new specification for creating an isolated WiFi network that consists of just a mobile device and a TV, no wireless router or Internet connection required. The difficult tasks of establishing a secure, password-protected network and ensuring that videos stream in the correct codec and at the appropriate resolution will in theory be handled automatically with no user frustration.

Will vendors really cooperate?

There's little reason to believe Miracast will provide interoperability amongst all devices. Vendor cooperation is required, and it's hard to imagine Apple and all other vendors with proprietary implementations will play nicely with Miracast. But where others have failed, Miracast may well succeed in creating a widely used protocol for vendor-neutral, routerless media streaming. So what is it?

You may remember WiFi Direct, a previous WiFi Alliance program that promised peer-to-peer wireless connections without a router. WiFi Direct hasn’t exactly revolutionized home networking, but it isn’t dead and it’s not going away—Miracast relies heavily on the WiFi Direct technology.

Just as WiFi Direct builds on top of the core 802.11 wireless networking standards, Miracast builds on WiFi Direct to make it more user-friendly.

WiFi Direct-certified devices can discover each other and pair up, using the same wireless protocols and security standards as WiFi, but without an access point, explains WiFi Alliance Senior Marketing Manager Kevin Robinson.

What Miracast adds is "the ability to negotiate the particulars of streaming audio and video," Robinson said. "There are common codecs that all of these devices can support, common resolutions that all these devices support, mechanisms to negotiate the best possible resolution between devices. It's all the additional negotiation that needs to happen to make the audio and video experience as seamless as possible to the user. They don't have to worry about whether the other device has the right codec or resolution."

The connections made between two or more devices use the same security mechanisms as traditional WiFi, but are standalone WiFi networks isolated from any other wireless network. ‘These devices are only communicating with each other,” Robinson said.

If the smartphone-to-TV streaming use case sounds a lot like AirPlay, that's because it is, minus the Apple devices. "You can absolutely view it as an equivalent to AirPlay, at a high level," said Broadcom's Dino Bekis, senior director of the company's access and wireless entertainment unit. "It's really intended to share video and other content on non-Apple devices."

The difference is that the Miracast certification is designed to guarantee interoperability across devices from different vendors, although we wouldn't put it past vendors to try to turn their own versions of Miracast into proprietary implementations.

Miracast’s certification program is planned for a launch sometime in Q3 2012, which started this month. The program launch date is when devices can start the certification process, Robinson said. While the participants in the program are technically confidential, Robinson notes that various chipset vendors have made public pronouncements about Miracast plans, including Texas Instruments, Qualcomm Atheros, Broadcom, Marvell, and Cavium.

A new chip from Marvell, for example, supports both the upcoming 802.11ac wireless standard and Miracast.

In most cases, Miracast can be implemented in software alone, Robinson said. It has a head start, because Android already supports WiFi Direct since version 4.0. But hardware modifications will help optimize devices for the type of compression, decoding, and encoding Miracast equipment will have to perform, he said.

Vendors who belong to the WiFi Alliance are hoping to release marquee Miracast products this holiday season and gain broader proliferation next spring, according to WiFi Alliance Marketing Director Kelly Davis-Felner.

Miracast's friendly competition: 7Gbps streaming over 60GHz

One potential problem for Miracast is confusion over its place in the technology market. Besides the various competing proprietary setups, there are the WiFi Alliance’s own plans for 60GHz products based on the emerging 802.11ad wireless standard. While traditional WiFi products use the 2.4 and 5 GHz bands, 802.11ad focuses on the higher-throughput, shorter-range 60GHz band.

802.11ad is thus optimized for high-speed data transfers and media streaming. As as we’ve reported before, the first 11ad products will likely be point-to-point setups with no routers—just like Miracast.

Miracast will not work on 60GHz technology, at least at first. This raises a couple of questions. If 60GHz products are faster and perform point-to-point transmissions, why is Miracast necessary? Alternatively, if Miracast is the simplest method of setting up a mobile device-to-TV streaming session, what’s 60GHz good for?

Miracast has an advantage over 802.11ad in that its development is a lot further along, since it’s based on the existing 802.11n wireless standard. It’s expected that 60GHz products won’t be certified until late 2013.

Miracast could work on top of 60GHz transmissions and the other emerging standard for 5GHz transmissions, 802.11ac, providing the best of both worlds. But no commitment on timing has been made by vendors—for now, they are planning separate products for Miracast, 802.11ac, and 802.11ad. It's not yet clear whether Miracast or some other streaming service will be used over 60GHz airwaves, Robinson said.

‘There aren't really public announcements in terms of commitment to port Miracast onto 60GHz,” Robinson said. “But clearly this is a technology and program that would be very useful not only in 60GHz but also in the upcoming 5GHz program based on 802.11ac.”

Porting onto 802.11ac will likely be easier than porting onto 60GHz. While Miracast must run over 2.4GHz to negotiate a connection between two devices, it can already stream over the 5GHz band once the connection is made, making it a natural fit for the Gigabit per second speeds of 802.11ac.

802.11ad promises speeds of 7Gbps, but is on a longer development timeline since it runs on an unfamiliar band for WiFi. To find out how 60GHz products will handle streaming of video traffic in the absence of Miracast support, we contacted Wilocity, a chip vendor planning some of the first 60GHz products.

The message from Wilocity is that WiFi-certified 802.11ad products will be interoperable with each other and easy to use, but separate from Miracast.

“Miracast is defined as a way to move video from point to point over the existing IP network, where there was not a clearly defined way to do so before,” Wilocity VP of marketing Mark Grodzinsky says. “Miracast defines the codecs and all other details that are required for interoperability over the basic MAC layer.”

60GHz, or “WiGig” as it also known, “is defined as an optimized video tunnel, which is a Protocol Adaptation Layer that sits on top of the MAC, and defines how video communications will be done, and is not transported over the IP network,” Grodzinsky continued. “WiGig had the luxury of creating a solution from scratch, optimized for video, which can go from lightly compressed all the way to uncompressed streams.”

Ultimately, 802.11ad is “as well defined and easy to use as Miracast; they just do things a bit differently,” he said.

First-mover advantage goes to Miracast

In any case, Miracast is coming first, and the WiFi Alliance is confident this is the certification that’s needed to get the kind of cross-vendor interoperability that wasn’t achieved by WiFi Direct on its own.

“We’ve certified a lot of devices for WiFi Direct, and a lot of those devices we’ve certified are things like TVs and set-top boxes,” said Kelly Davis-Felner. But “what we’re seeing in early implementations of WiFi Direct is much more vendor-specific” than would be ideal. Samsung and Sony have their own implementations, for example.

WiFi Direct was cross-vendor, but very much driven by Intel. Miracast, by contrast, "is actually one of the biggest task groups we've ever had in the WiFi Alliance," Davis-Felner said. "It would not be fair to say Intel is leading it by any stretch of the imagination. There are numerous companies involved."

Bekis notes that while 802.11ad is in its infancy and will require new hardware, “the reason Miracast is moving faster is you already have millions of deployed devices today that support WiFi.”

The WiFi Alliance cautions that customers can’t be sure of interoperability unless a product is certified as compliant with the Miracast spec. But Bekis notes that many products on the market already could conceivably run Miracast, even though the certification isn’t available yet.

‘Miracast is going to be a very common denominator across all these devices for the foreseeable future and the primary vehicle for sharing video wirelessly,” Bekis predicted.

15 Reader Comments

There's little reason to believe Miracast will provide interoperability amongst all devices. Vendor cooperation is required, and it's hard to imagine Apple and all other vendors with proprietary implementations will play nicely with Miracast. But where others have failed, Miracast may well succeed in creating a widely used protocol for vendor-neutral, routerless media streaming. So what is it?

Wi-FI Alliance has pushed stuff similar to Miracast on vendors before, for example in order to implement 802.11a/b/n/g your device MUST support WPS, even though the standard itself can be implemented in such a way that it contains a major security hole. Even after they have determine that the WPS standard is basically broken ( unless you implement it in a very specific way that Apple happens to use ) you cannot place the Wi-Fi Alliance seal on your product without supporting WPS. This means without this seal you cannot advertise that your product supports 802.11a/b/n/g as said industry group holds the copyright on said seal.

So the simple solution to this vendor specific "AirPlay" problem is to force ALL vendors to support Miracast. We have 802.11/ac being released, in theory they could force all vendors to support Miracast, and thus Apple, Microsoft, Sony, and Google would be required to support this standard.

In the end it won't matter if Apple has AirPlay, if they want the seal and thus the permission to say sell a Apple TV that supports 802.11/ac then they will have to support both, it sounds like a pure software solution is possible.

If there was a way to combine my licenses from Apple, Microsoft and Google I would be very happy.

Can some-one point me in the direction of a technological explanation of how Wi-Fi, Wi-Fi direct et al work on a technical level? My basic knowledge of networking brings up the OSI model, with physical, data link etc. layers. However Wi-Fi seems to merge these together. For example I cannot buy a Wi-Fi hub that simply repeats a Wi-Fi network (which I would have thought was levels 1 and 2) on a different channel, it appears the Wi-Fi box needs to be a node on the IP network.

Similarly with Wi-Fi Direct and Miracast (Side Q: What is the Mira prefix? did they just steal it from Qualcomm)? Why is Miracast not an Application Level protocol that can run atop any network connection (IP Network)? My forays into Apple's protocols (Mainly DAAP, but Airplay seems to be a variant of it) seem to say all you need is a Zeroconf service and a HTTP server/client, and you can run it over anything, Wired, Wireless whatever.

Phantom, I don't see Apple being forced to implement a Miracast just to get a sticker on their boxes as they clearly want people to use airplay . Apple has just abandoned EPEAT because EPEAT makes easy disassembly a prerequisite. Apple could just make Miracast an expensive option or furnish just enough support to pass the WIFI alliance cert tests without making it usable.

I think/hope this Miracast work also as full screen wireless mirroring (like Apple AirPlay / Intel WiDi), instead of just streaming video/audio. Yes I'd welcome an "industry standard" that allows mirroring and streaming from all devices (including AMD laptops, all brand smartphones and tablets). I doubt Apple will go along though.

I don't understand the requirement to do away with an existing Wi-Fi network. If I understand this correctly, when in Miracast mode, the devices involved are locked out from other Wi-Fi-networks. That is, if I use my smartphone to stream music to my home entertainment system, I cannot also use my smartphones Wi-Fi connection to connect to the Internet. If so, this seems like a major drawback, compared to AirPlay.

tigas wrote:

XBMC "Eden" supports Airplay, no need to shackle youself to Apple

Well, several 3rd party products support Airplay, but they're all reverse engineered hacks in one way or another, with specific trade offs, and/or have buggy behaviour.

I can only hope that Miracast or some other platform-independent industry standard takes hold enough that Apple is compelled to adopt it. Airplay is great for consumers at home, but it is simply not serviceable in an enterprise environment due to its reliance on mDNS, shared wireless infrastructure, and overall poorly implemented pairing and access controls.

I stream audio and video from all my Android devices to my Samsung Series 8 TV set, as well as to my Denon amplifier, using "Twonky".

Twonky is a free app the Play Store (ie "Android Market") and gives your devices the ability to act as a DLNA server. It does not require your devices to be "rooted". It scans your network for compatible DLNA devices and gives you the option to send the stream to another device using the normal "share" function in Android. It streams local media files of virtually any kind, as well as YouTube videos.

In addition to this, Windows Home Server and all recent Windows machines can share media using DLNA streaming. It takes 10 seconds to get it running, using the built-in media player.

The technology and software is already available to anyone with an Android device or Windows device and a compatible DLNA device. I bet iOS can do some of the same too, one way or another.

The TV is 2 years old, and my Android devices are nothing special (Galaxy S WiFi and a Nexus S phone - both "old" single-core devices by modern standards).

What exactly is this new "Miracast" supposed to do in addition to what we already have (and have had for years)?

I stream audio and video from all my Android devices to my Samsung Series 8 TV set, as well as to my Denon amplifier, using "Twonky".

Twonky is a free app the Play Store (ie "Android Market") and gives your devices the ability to act as a DLNA server. It does not require your devices to be "rooted". It scans your network for compatible DLNA devices and gives you the option to send the stream to another device using the normal "share" function in Android. It streams local media files of virtually any kind, as well as YouTube videos.

In addition to this, Windows Home Server and all recent Windows machines can share media using DLNA streaming. It takes 10 seconds to get it running, using the built-in media player.

The technology and software is already available to anyone with an Android device or Windows device and a compatible DLNA device. I bet iOS can do some of the same too, one way or another.

The TV is 2 years old, and my Android devices are nothing special (Galaxy S WiFi and a Nexus S phone - both "old" single-core devices by modern standards).

What exactly is this new "Miracast" supposed to do in addition to what we already have (and have had for years)?

Seems a little (or even a lot) pointless. When DLNA is so easily accessed by Android Apps, TV's, XBox, PS3, Boxee, Blu-Ray players. There is just not a lot of clamoring for it. Shoot, I can "flick" pictures to my TV using the Fios Box!